Tray former

ABSTRACT

A machine for forming shipping cases or trays from flat blanks having a storage magazine, stripping means for removing one blank at a time from the magazine, glue-applying means for selectively applying glue to desired portions of the blank, an indexing means for advancing the blank past the glue-applying means to a trayforming mandrel, and means cooperative with the mandrel for folding up the sides of the blank and folding the ends thereof in threefold overlapping relation.

VII 1 L Milled lame Plenll [1-51 396359129 film/hello, J11, [4 51 ,Man, 18, 1972 [54] TRAY FORD/HIE 3,218,940 11/1965 Pearson ..93/51 [72] Inventor: Vincent Cobelo, J12, Dunedin, Fla. Primary Examiner wayne A. Morse Jr. [73] Aasignee: AMI Packaging Machine (Iorporation Assistant Examiner-Eugene Desmond Attorney-Newton, Hopkins & Ormsby I22] Filed: Sept. M, i969 [2| Appl. No.: 857.70% AB TRACT A machine for forming shipping cases or trays from flat blanks 521 11.5. cu .93/51 n, 53/192, 93/36 MM, having a Storage magazine, Stripping means for removing one 93/49 AC blank at a time from the magazine, glue-applying means for 51 1111.101 ..B3lb 1/44 Selectively p y glue to desired portions of the blank, an 58 1 1mm of! Search ..93/51, 5 1 M, 36 MM, 99 AC; indexing means for advancing the blank P the pp y 53/192, 194 means to a tray-forming mandrel, and means cooperative with the mandrel for folding up the sides of the blank and folding 55 R f e Cited the ends thereof in threefold overlapping relation.

UNITED STATES PATENTS 6 Claims, 17 Drawing Figures 3,046,849 7/ l 96 2 V Bowmanm, ..93/51 25 g I l 1 1 1 l I 1 49 1 I1 VACUUM pu/p p PATENIEnJmamz 3.635.129

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PATENTEBJMII amz SHEET [15 0F 16 mmmm 3535129 SHEET O7DF 16 FJG I PATENTED JMIBWZ 3,635,129

SHEET [38 0F 16 PATENTED N 1 8 B72 sum new we PATENTEB M i 8 I972 SHEET ROOF 16 ED .mu 3 m2 SHEE 3 0F 16 v mrk mm NS BACKGROUND OF TIIE INVENTION This invention relates generally to shipping case or tray formin machines and more articular-l to a machine for setting up shipping cases or trays from blank forms, folding and sealing the flaps to wholly form the end and sidewalls thereof, and delivering the thus setup cases for packing or otherwise.

In shipping or storing various articles such as food, beverages or other products, it is customary to place them in shipping or packing cases constructed of heavy fibrous material, for example, corrugated board or pasteboard or the like. Such a corrugated case, having one open end for packing, is typically used in packing tomatoes, lettuce, and other vegetables and products wherein overlapping end panels are provided for strength and securement.

The shipping cases or trays come from the manufacturer packaged in bundles of flat blanks for convenience in handling. In the past these blanks were removed one at a time from their shipping bundle and set up by hand. But today, manymachines for forming shipping trays are being widely used in the packaging industry. These machines for the most part, however, are generally bulky and require highly complicated camming and gearing arrangements. For these reasons, machines of this kind are very expensive to construct and also costly to maintain. Moreover, the machines now on the market operate slowly and many require skilled operators to supervise their performance.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to pro vide an improved machine for forming shipping cases or trays from flat blanks and folding and sealing the flaps thereof in a 3 5 closed position.

Another object of this invention is to provide a machine for forming shipping trays from blanks which will operate with the minimum of attention other than keeping the supply magazine thereof filled with the blanks.

Still another object of this invention is to provide a machine for forming shipping tray blanks which is fast and economical in operation, and simple and inexpensive in construction.

The foregoing and other objects, advantages and features are attained by a machine featuring a mandrel which engages the bottom panel of a tray-forming, corrugated blank during a downward travel and successively, during the advancement thereof, engages flap tuckers on one side thereof for folding a side panel upward against the mandrel and the end panels thereon inward about the mandrel, then engages another set of flap tuckers on the opposite side for folding another side panel up against the mandrel and end panels thereon inward about the mandrel and overlapping the first end panels, and finally engages a third set of flap tuckers on the ends thereof for folding up end flaps against the mandrel overlapping the overlapped end flaps formed from the side panels. An adhesive applied to the blank prior to engagement by the mandrel secures the folded and overlapped panels together. Upon retraction of the mandrel for receiving another blank, the tray or case thus set up is discharged from the bottom of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of the overall machine constructed in accordance with the present invention;

FIG. 2 is a schematic showing the sequential steps in forming a tray with the machine ofFIG. I;

FIG. 3 is a longitudinal cross-sectional view of part of the machine;

FIG. 4 is a longitudinal cross-sectional view of the rest of the machine shown in FIG. 3;

FIG. 5 is a partial top view showing the pulldown assembly and blank-advancing mechanism of the machine;

FIG. 6 is a cross-sectional view taken along the line ti-6 of FIG. I;

FIG. '7 is a cross-sectional view taken along line 77 of FIG.

FIG. 3 is an enlarged top view of one of the flap folders; FIG. 9 is an enlarged side view of the flap folder taken along line 9-9 in FIG. 8;

FIG. III is an enlarged view taken along the line III-10 of FIG. 8;

FIG. III is a perspective view showing the leading flap being folded;

FIG. I2 is a perspective view showing the trailing flap being folded;

FIG. I3 is a perspective view showing the middle end flaps being folded;

FIG. I4 is a perspective view showing the tray being stripped from the mandrel;

FIG. I5 is an enlarged view partly broken away to illustrate the vacuum selector valve assembly;

FIG. 16 is an electrical control schematic; and, FIG. I7 is a pneumatic control schematic.

DESCRIPTION OF AN ILLUSTRATED EMBODIMENT Referring now to the drawings wherein like reference numetals are used to designate like or corresponding parts throughout the several views and more particularly to FIG. 2 thereof, there is shown a shipping case or tray indicated generally by the reference numeral III, constructed of corrugated board, pasteboard or the like, in the collapsed blank form as received from the manufacturer and in the various successive stages in which it is normally set up for use. The shipping case or tray I0 comprises a rectangular bottom end II, a pair of sidewalls I2 and 12 connected to the bottom II along the longitudinal edges thereof and each having end flaps I3 and I3, respectively, thereon and an end wall or flap 14 connected to each lateral edge of the bottom I1. Although illustrated herein as being generally rectangular in configuration, the cases or trays 10 may also be square, if desired.

The blank 10 is designed to be set up by bending the material of the side and end walls and the flap surfaces thereon along creases or score lines I5 which are provided at the corners. .One of the sides I2 is folded at right angles to the bottom ll and the flaps l3 thereon, which will be referred to hereinafter as the leading flaps, are folded inward at right angles to the side I2 and the bottom I1. The other side I2 is folded at right angles to the bottom 11 and the flaps I3 thereon, which will be referred to hereinafter as the intermediate flaps, are folded inward at right angles to the side 12' and the bottom II to overlap the leading flaps I3. Finally, the end flaps I4, hereinafter to be referred to as the outer flaps, are folded upward over the intermediate flaps I3. When folded in the manner indicated and secured as by gluing, a tray I0 is formed having the general appearance shown in FIG. 2. Slots 16 in the end flaps I3, I3 and Id provide convenient handholes for carrying the tray.

In reference now to the operation of the tray-forming machine and tracing the progress of a blank 10 through the machine, the blank forms are removed one at a time from a storage magazine I7 by a pulldown assembly 18 and conveyed to a mandrel III as best seen in FIGS. 3, I, and S. The stack of blanks III are supported on parallel guide bars 20 longitudinally disposed along the edges of the magazine I7 in the direction of travel of the blanks to the mandrel.

The pulldown assembly I3 comprises a set of vacuum cups 21 secured to a support 22 movably disposed in a vertical reciprocable path with the piston rod 23 of an air cylinder 24 mounted on the frame 25 of the machine. Also secured to the support 22 and positioned therebeneath. for vertical disposition therewith is an elongated, collar 26 slidably fitting on an upright follower member 27 secured to the air cylinder 24 in parallel relationship therewith. A crank 28 is pivotally received at one end thereof between a pair of parallel flanges 29 on the collar 26 and is pivotally connected at its other end to an arm 30. The arm 30 is keyed to a shaft 3I journaled in bearings, not shown, in the frame 25 to which the ends of a pair of parallel arms or levers 32 are also secured to rotate about the axis thereof with the shaft 31. iivotally connected to the other end of each lever 32 is a connecting link 33 pivotally mounted at its other end to an advancing bar 34 slidabiy disposed in channels 35 for movement reciprocably along a line of motion perpendicular to the line of motion of the pulldown rod 23. A positioning finger 36 is pivotally mounted on each advancing bar 34 at the forward end thereof for positively locating the blank under the mandrel 19 in the manner to be set forth hereinafter.

A set of parallel chains 37 for transferring the blanks 10 from the magazine area to the vicinity of the mandrel 19 are disposed on sprocket wheels 38 that are drivingly connected with a spur gear 39. The spur gear 39 is turned by the output shaft and associated gearing of a speed reducer mechanism 40. A pair of lugs 41 are fastened to each transferring chain 37 for carrying theblank 10 forward under a plurality of glue heads 42 where a hot melt applicator associated therewith applies strips of adhesive 43 to the flaps 13 and 14 (FIG. 2) from a hot melt glue tank 44. Special limit switches 45 and 46 positioned between the glue applicators are provided with biased rollers for contacting the blank tray form 10 and detecting the thickness thereof. Limit switch 45 shuts off the machine till the trays are cleared if a double thickness is detected, as by more than a single tray being pulled from the magazine 17 by the pulldown assembly 18, and limit switch 46 prevents activation of the glue application circuit if no tray arrives at the gluing station. Another limit switch 47 on the frame 25 adjacent the chain drive 48 driven by motor 49 through reducer 40 is provided with a spring-biased roller 50 and is operably associated with the glue application circuit. Cutting off the application of glue for preventing the application of glue to the handholes 16 and the space between the flaps is accomplished by actuating the switch 417 with a cam 51 on the drive shaft 52 of the chain drive 48 having special skipping lugs L attached thereto.

Accordingly, stacked trays 10 in the magazine 17 are timestripped into the transferring chains 37 by the pulldown assembly mounted below the magazine 17. The transferring chains 37, through the lugs 41 thereon, carry the tray under the glue heads 42 and partially to the forming station, where the mandrel 19 is positioned. On the next reciprocation of the assembly 18, the positioning fingers 36 are retracted by links 33 to take over where the transfer chains 37 leave off and carry the tray 10 the rest of the way into the forming station under the elevated mandrel 19. The positioning fingers 36 move the blank 10 into the fonning station until arrested by stops to make a switch 53 that activates the forming or mandrel cylinder 54 to cause the mandrel 19 to descend as shown in FIG. 4.

Referring now more particularly to FlGS. 4 and 6-9, the airdriven mandrel 19 is mounted on frame 25 above the path along which tray blank 10 is moved and is appropriately connected to piston rod 55 of cylinder 54 to be reciprocally mova ble along a vertical line of motion perpendicular to the line of motion alongwhich the tray is transferred past the glue heads 42. As has already been explained, when the blank 10 engages and activates switch 53 the air cylinder 54 is activated to extend piston rod 55 downwardly and cause the blank 10 to be carried therewith to form the completed tray 10. As the blank 10 is moved downwardly by the mandrel 19, the leading sidewall 12 thereof is first engaged by a pair of leading flap folding guides 100 which are inclined downwardly from frame 25 toward the path of the mandrel 19 and then curved downwardly parallel to the desired path of the blank 10 with the leading sidewall 12 folded. The guides 100 cause the leading sidewall 12 to be folded up against the side of the mandrel 19 by bending along the creases or line and is held thereagainst as best seen in FIG. 11. As the mandrel 19 continues to move the blank 10 downwardly the bottom of the blank 10 engages a first pair of leading flap folders 101 which fold the leading end flaps or first folded end flaps 13 integral with the sidewall 1.2 up against the sides of the mandrel 19 as seen in FIG. 11.

In the meantime, the trailing sidewall 12 of the blank 10 has been engaged by a pair of trailing folding guides 102 which fold the trailing sidewall 12' as the guides fold the leading sidewall 12. As the mandrel 19 continues to move the blank 10 downwardly, the trailing end flaps 13' attached to wall 12 are engaged by a second pair of flap folders 105 which fold the end flaps 13 over the already folded leading end flaps 13. Since the lines of glue 43 have already been applied to the inside surface of the trailing end flaps 13, the glue attaches the already folded leading end flaps 13 to the new folded trailing end flaps 13.

The mandrel 19 continues to move the partially formed tray 10 downwardly between compression plates 106 which have outwardly flared portions 108 that engage the end walls 14 attached to the bottom 11 of the tray 10 and fold them upwardly over the already folded trailing end flaps 13. Since the lines of glue 43 have already been applied to the inside surface of the walls 14, the glue serves to attach the end walls 14 to the trailing end flaps 13'. The mandrel 19 continues to move the thusly formed tray 10 downwardly into the position shown in FIG. 4 so that the compression plates 106 press the flaps l3 and 13 and the walls 14 together until the glue has set thereby producing the formed tray 10.

The flap folders 101 and 105 are mirror images of each other. Therefore, only one of the flap folders 101 will be described in detail with primes of the referenced numerals applied thereto being applied to corresponding parts of the other flap folders. Referring specifically to FIGS. 8-10, it will be seen that the flap folder 101 includes a support 110 which is mounted on a transversely extending shaft 111 rotatably journaled in the frame 25, as seen in FIG. 7 and constantly urged in a counterclockwise direction as indicated in FIG. 9 by spring 112 shown in FIG. 7. The support member 110 has a U- shaped transverse cross section as best seen in FIG. 8 with an inner wall 114 and an outer wall 115 joined by web 113 defining a recess 116 extending along the length thereof.

A folding assembly 120 is mounted at the upper or outwardly extending end of the support member 110 adjacent the inner wall 114 thereof. The flap-folding assembly 120 is mounted on a U-shaped support bracket 121 having a pair of mounting spaced legs 122 which extend above or inwardly of I the inner wall of the support 110. Pivotally mounted between the legs 122 is an L-shaped arm 124 having a long flap folding leg 125 and a short camming leg 126. Arm 124 pivoted about cropp-pin 128 extending through pivot block 129 carrying the arm 124 and the legs 122 of the mounting bracket 121. The arm 124 is adapted for pivotal movement between a closed position shown in solid lines in FIG. 8 and an open position shown in dashed lines in FIG. 8. As the arm 124 moves from its open position to its closed position, it folds one of the end flaps 13 of the tray blank 10.

For maintaining the arm 124 in its open position or its closed position, a spring 130 is provided which extends between the pivot block 129 and the mounting bracket 121 in such a manner that when the arm 124 is forced into its closed position it will be maintained in that position because the pin 131 connecting the spring 130 to the pivot block 129 lies on the left side of the pivot pin 128 as is seen in FIG. 8. On the other hand spring 130 will force the arm 124 toward its open position once the arm 124 is shifted so that the pin 131 lies to the right of the pivot pin 128 as shown by the dashed lines in FIG. 8. In this manner, once the arm 144 is shifted to either position, it will be held there under the influence of spring 130. When the support 110 is pivoted counterclockwise as shown in FIG. 9, a cam 132, best seen in FIGS. 8 and 10, will extend through an appropriate aperture 134 through support 110 and opening into recess 116 to engage the edge of a depending cam 135 on cam leg 126 of arm 124 and move the arm 124 sufiiciently far clockwise as seen in FIG. 8 to cause the arm 124 to be moved to its open position. This takes place when the mandrel 19 is moved upwardly from between the flap folders 101 and 105 and the arm 124 will remain in this position until the mandrel 19 again is moved downwardly carrying a tray blank 10 therewith. As the mandrel 19 moves downwardly, the sidewall l2 engages the cam of the leg i126 and cause to pivot to its closed position while folding one of the end flaps E13 by the flap-folding leg l25.

As the mandrel W moves downwardly, carrying the tray blank l therewith, the support is pivoted clockwise against the spring 112 by the blank l0 engaging driving plate 136 carried by the support HM and extending therebelow as seen in FlG. i. it is the combined action of the pivoting of the support llllll about the shaft Ell-l and pivotal mounting of the arm 12 that causes the arm R24 to move from its open position to its closed position while at the same time causing the flap 13 to be folded against the mandrel 19. The driving plate 11% is of sufficient length that the mandrel B) will cause the formed tray llll to be displaced below the lower end thereof when it is in final compression position between the compression plates llllli so that the driving plate i396, under the influence H2 is pivoted inwardly against the side of themandrel 19 as best seen in FlG. ll l so that, when the mandrel l9 begins its ascent, the lower edge of the plate lllilti will engage one side of the formed tray lb and cause it to be stripped from the mandrel l9 in'conjunction with the complimentary plates of the trailing flap folding assemblies Mk as set forth hereinbelow. The driving plates llIlda of the trailing flap folders llllS as seen in lFlG. l are shorter than the corresponding driving plates 13d and 13th of the flap folders Mil so that when the flap folders lllll and M95 are pivoted to a substantially vertical position is seen in lFllG. 14-, the lower ends of the plates lldb, 136' and llEllia lie in substantially the same horizontal plane. in this manner, it will be seen that these plates engage the top of the formed tray llll and strip the same from the mandrel l9 as it ascends. The tray ill is held between the compression plate d until the next tray ltl is formed and occupies the position shown in FlG. l. This causes the first formed tray ill to be discharged below the compression plates the onto a suitable conveyor (not shown) to be moved out of the machine. Since the glue applied to the flaps l3 and end walls lid of the tray 110 is of the hot glue or quick setting type, the length of time that the tray llll is held between the compression plates 1% is sufficicnt for the glue to set up and the finally discharged tray ill will be ready for use.

From the foregoing description it will be seen that the sidewalls lit and t2, the end flaps l3 and lit, and the end walls 14 are all folded to form the final tray llfl upon reciprocation on mandrel 119. Thus, the mandrel M serves as the only external power source that is needed to completely form each tray 110.

In FIG. l5, there is shown a special selector valve assembly 1150 that may be provided if desired should the operator wish to keep the machine operating without running trays therethrough. in the position shown, the vacuum is activated by cam l5]! on shaft Ell through valve ill. When the handle 152 connected to a secondary cam i5 1 is rotated counterclockwise as seen in HG. 115 to its manual position, it prevents cam follower 1155 from contacting cam ll5ll and shuts off the vacuum to the pulldown assembly l8.

FIG. lid is a schematic of an electrical circuit for controlling the machine disclosed herein and shows the main drive motor 49 and a vacuum pump motor 73 belted thereto connected with parallel circuits for the hot melting applicator, the hot melt heaters and the mandrel or forming head cylinder. The glue applicator limit valves M and 47 are shown in the normal closed positions. Limit valve did is normally in the open position, which is the case when no tray blank is in the glue application area. Qther limit valves 5'3 actuated by the tray blank 110 fully positioned under the mandrel for starting the mandrel downward and 74 for initiating retraction of the mandrel are shown operatively connected to solenoids 7a and 7'7 for moving a pneumatic valve '78 to effect the operation of the air driven mandrel l9.

FIG. ll'l" is a schematic of atypical pneumatic circuit for the present machine and shows a main fluid line leading from an air supply under pressure to the system. Line pressure till feeds to a line for actuating an air cylinder 82 of a springbiased valve and to a line 64 to the inlet of the valve 83. A cam-actuated valve 355 is disposed in the line all. Two outlet lines as and 87 from the valve 83 lead to the pulldown assembly actuating cylinder 24 for controlling the stripping of tray blanks llll from the magazine H7. The vacuum for the cups Zl of the pulldown assembly M5 is provided by pump 73 which is connected thereto through a spring-biased valve ilk having an inlet line $9 and an outlet line 9G and actuated by the application of line pressure 30 thereto through a cam-actuated valve 9i and a fluid line 92 therebetween.

Application of the hot melt (l2 through a cylinder thereof is controlled by admitting line pressure bill thereto through a solenoid-actuated valve 93 and through outlet lines 94 and 95 therefrom to one side of the cylinder.

Reciprocable motion of the mandrel IE9 is accomplished by moving a piston 96 within the cylinder 54. Such motion is achieved by the alternate and successive admission of line pressure fill through a valve '78 actuated by solenoids 76 and 77 to lines 97 and 98 leading to both sides of the cylinder 54.

Obviously, many modifications and variations of the present invention are possible in the light of the: above teachings. lt is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

ll. in a machine for automatically setting up shipping trays from blank forms, the combination comprising:

a magazine for storing a supply of said tray blanks for said machine;

means for removing said tray blanks one at a time from said magazine;

glue-applying means for selectively applying glue to predetermined portions of said tray blanks;

indexing means for advancing tray blanks past said glue-arr plying means to a tray-forming station; and

means disposed at the tray-forming station for folding the side panels of said tray at right angles to the tray bottom and successively folding the end flaps of one of said folded panels, the end flaps of the other of said folded panels and the end flaps of said tray bottom in overlapping relation and at right angles to said folded side panels and said tray bottom, said tray-forming station comprising;

a mandrel having a configuration substantially like that of the tray blank when set up, and being movably disposed in a reciprocable path perpendicular to the plane of said tray blank received at said tray-forming station, said mandrel being positioned to engage said tray blank on the bot tom panel thereof upon movement in one direction;

means on one side of said mandrel path for engaging a side panel of said tray blank and folding said side panel against the mandrel when said mandrel and said tray blank are moved thereby;

means on the other side of said mandrel path for engaging the opposite side panel of said tray blank and folding said opposite side panel against the mandrel when said mandrel and said tray are moved thereby;

a pair of flap folders disposed on said side panel engaging means for folding the end flaps of said side panel about the mandrel ends;

another pair of flap folders disposed on said opposite side panel engaging means for folding the end flaps of said opposite side panel about the mandrel ends overlapping the flaps of said side panel; and

means on the end sides of the mandrel path for engaging the end flaps of the tray bottom and folding said end flaps about the mandrel ends overlapping the folded end flaps of said opposite side panel;

each of the flap folders which fold the end flaps of the side panels comprising;

a mount having an opening therein; 

1. In a machine for automatically setting up shipping trays from blank forms, the combination comprising: a magazine for storing a supply of said tray blanks for said machine; means for removing said tray blanks one at a time from said magazine; glue-applying means for selectively applying glue to predetermined portions of said tray blanks; indexing means for advancing tray blanks past said glue-applying means to a tray-forming station; and means disposed at the tray-forming station for folding the side panels of said tray at right angles to the tray bottom and successively folding the end flaps of one of said folded panels, the end fLaps of the other of said folded panels and the end flaps of said tray bottom in overlapping relation and at right angles to said folded side panels and said tray bottom, said tray-forming station comprising; a mandrel having a configuration substantially like that of the tray blank when set up, and being movably disposed in a reciprocable path perpendicular to the plane of said tray blank received at said tray-forming station, said mandrel being positioned to engage said tray blank on the bottom panel thereof upon movement in one direction; means on one side of said mandrel path for engaging a side panel of said tray blank and folding said side panel against the mandrel when said mandrel and said tray blank are moved thereby; means on the other side of said mandrel path for engaging the opposite side panel of said tray blank and folding said opposite side panel against the mandrel when said mandrel and said tray are moved thereby; a pair of flap folders disposed on said side panel engaging means for folding the end flaps of said side panel about the mandrel ends; another pair of flap folders disposed on said opposite side panel engaging means for folding the end flaps of said opposite side panel about the mandrel ends overlapping the flaps of said side panel; and means on the end sides of the mandrel path for engaging the end flaps of the tray bottom and folding said end flaps about the mandrel ends overlapping the folded end flaps of said opposite side panel; each of the flap folders which fold the end flaps of the side panels comprising; a mount having an opening therein; a flap arm pivotally disposed on said mount, said flap arm being alternately movable to one or the other of two positions and having a projecting cam surface at one end thereof movable in said opening in said mount when said arm is caused to move from one position to the other; and biasing means secured to said mount and said arm for alternately biasing said arm to one or the other of said two positions.
 2. The machine of claim 1 wherein said side panel engaging means and said opposite side panel engaging means are pivotally disposed about axes perpendicular to the path of movement of said mandrel, whereby said flap folders disposed thereon may be moved into and out of engagement with said mandrel upon movement thereof in one direction and movement in the other direction respectively; and means for contacting said cam surfaces of said flap arms upon movement of said mandrel in said other direction for pivoting said flap arm.
 3. The machine of claim 1 wherein said tray blanks are stored in said magazine stacked upon one another; and said means for removing said tray blanks from said magazine comprises a pulldown assembly for successively removing the lowermost tray blank from said stack along a line of motion perpendicular to the plane thereof.
 4. The machine of claim 3 wherein said tray blank removing means comprises vacuum cup means for engaging the blanks successively.
 5. A machine as in claim 1 further comprising a limit switch for stopping the machine if two or more tray blanks arrive simultaneously at the glue-applying means.
 6. A machine as in claim 1 further including a limit switch for stopping the machine if no tray blank arrives at the gluing means at the appointed time. 